The problem of writing in the dark or writing in poorly illuminated areas has occupied the attention of inventors for same time. Patents known by applicants to have issued are set forth below.
U.S. Pat. No. 1,345,962 to Sanders. This teaches the construction of a small flashlight simply clamped to the body of a writing instrument and focusing on the writing point.
U.S. Pat. No. 1,498,643 to Cawley. This patent discloses a light attached to the writing end of an instrument and includes a switch which turns the light on when the writing instrument makes contact with the paper.
U.S. Pat. No. 1,588,891 to Hug. This patent discloses a light detachably mounted on a pen and wired to a battery which is constructed to strap on to the wrist of the writer.
U.S. Pat. No. 4,047,017 to Herring. In this patent a flashlight is mounted to a writing instrument by means of an adjustable bracket and lever arrangement. This makes it possible to vary the field of illumination while writing and to fold up against the writing instrument when not in use.
In all of the prior art the source of illumination is external to the writing instrument and focuses thereon. The applicants are aware of no prior art in which the light forms an integral part of the writing instrument itself and none that would be particularly applicable to a ball point pen in which the light is integral or internal to the pen itself.
The growth and popularity of ball point pens has focused the attention on providing an illuminated pen of this type, while being compatible with the operating mechanism of such a pen.